Japanese Patent No. 4163490 and its UK counterpart GB 2396656 (Patent Literature 1) disclose a known vehicle door lock apparatus that includes a housing, a fork (latch plate), and a pawl (locking plate).
The housing includes a body (latch unit comprising a plastics body) and an actuator housing (actuator unit comprising a plastics housing). The body is fixed to a door that is openable and closable with respect to a vehicle frame (side wall). The actuator housing is affixed to (mounted on) the body. An entry opening (slot), into which a striker fixed to the vehicle frame can enter, is formed in the body. The fork (latch plate) is pivotably provided in the body. The fork is displaceable to a latched position, where the fork retains the striker in the entry opening, and to an unlatched position, where the fork allows the striker to separate from the entry opening. The pawl (locking plate) is pivotably provided in the body. The pawl fixes or releases the fork.
This known vehicle door lock apparatus includes a first sub-lever, a second sub-lever, a locking/unlocking lever, a knob lever, a linkage lever (straightly movable rack lever), and a detecting lever. The first sub-lever, the second sub-lever, the locking/unlocking lever, and the detecting lever are provided in the body. The knob lever and the linkage lever are provided in the actuator housing.
The first and second sub-levers are displaced in response to an opening operation being performed on a door handle, come into contact with an open lever that is fixed to the pawl (locking plate) so as to integrally pivot therewith, and are capable of causing the pawl (locking plate) to release the fork.
The locking/unlocking lever is capable of being displaced to a locked position, where the locking/unlocking lever retains the first and second sub-levers in a lock position where the first and second sub-levers are unable to come into contact with the open lever, and to an unlocked position, where the locking/unlocking lever does not retain the first and second sub-levers in the lock position. In the unlocked position, the locking/unlocking lever enables (allows) displacement of the fork located in the latched position to the unlatched position. In the locked position, the locking/unlocking lever disables displacement of the fork located in the latched position to the unlatched position.
The knob lever is coupled to a locking/unlocking door knob. The linkage lever (straightly movable rack lever) is disposed between the knob lever and the locking/unlocking lever. The knob lever pivots in response to an unlocking operation being performed on the locking/unlocking door knob to pull down the linkage lever and displaces the locking/unlocking lever from the locking position to the unlocking position. The knob lever pushes up the linkage lever in response to a locking operation being performed on the locking/unlocking knob and displaces the locking/unlocking lever from the unlocking position to the locking position.
An arm portion, a stopper portion, and a detecting projection are formed in the detecting lever. The arm portion is guided in a cam groove of the fork, whereby the detecting lever is linked (interlocked) with the fork and is displaceable from an unblocking position corresponding to the latched position to a blocking position corresponding to the unlatched position and vice versa. In the unblocking position, the detecting lever separates from the locking/unlocking lever. In the blocking position, the detecting lever contacts and stops, via the stopper portion, the locking/unlocking lever located in the unlocking position and inhibits (prevents, blocks) the locking/unlocking lever from being displaced to the locking position. Further, the detecting lever detects whether the fork is located in the latched position or in the unlatched position and the detecting projection disconnects or connects a switch.
In this known vehicle door lock apparatus, when the fork is located in the unlatched position, the locking/unlocking lever located in the unlocking position contacts and is stopped by the detecting lever that has been displaced to the blocking position so that the locking/unlocking lever is inhibited (blocked) from being displaced to the locking position. In this state, even if a user (vehicle occupant) attempts to perform a locking operation in which the knob lever would normally pivot, pivoting of the knob lever is prevented (blocked) by the linkage lever, the locking/unlocking lever, and the detecting lever. As a result, the locking operation attempted by the user is prevented.
However, in this known vehicle door lock apparatus, since the pivoting of the knob lever is prevented (blocked) by three components (i.e. the linkage lever, the locking/unlocking lever, and the detecting lever), rattling among the components tends to accumulate and it is difficult to improve blocking rigidity (stiffness, resistance) with respect to the knob lever.
Furthermore, the detecting lever of this known vehicle door lock apparatus must perform the functions of (i) linking with the fork, (ii) contacting and stopping (blocking) the locking/unlocking lever, (iii) detecting the position of the fork and (iv) disconnecting or connecting the switch. Therefore, the fork, the locking/unlocking lever, the detecting lever, and the switch have to be disposed in positions close to one another, whereby it becomes difficult to design a vehicle door lock apparatus so that the thickness of the vehicle door lock apparatus in the vehicle inward-outward direction can be reduced.